The use of magnetic bearings in rotary machines such as centrifugal gas compressors is increasing. Magnetic bearings work on the principle of electromagnetic suspension. The use of electromagnetic suspension reduces or eliminates friction losses in centrifugal gas compressors.
Magnetic bearings in rotary machines are generally arranged with multiple windings or electric coils surrounding a shaft formed from a ferromagnetic material. Some magnetic bearings use a ferromagnetic lamination on the shaft when the shaft is not formed from a ferromagnetic material. The windings in a radial magnetic bearing radially surround the shaft and produce a magnetic field that tends to attract the rotor shaft. The attractive forces of the windings may be controlled by varying the current in each winding.
U.S. Pat. No. 8,072,104 to M. Korista discloses a magnetic bearing that includes a laminated bearing journal with a shaft-mounted rotating lamination and a corresponding housing-mounted stationary lamination surrounding the rotating lamination, whereby both laminations extend axially to the shaft within a bearing portion, limited on one side by the end of the shaft.
The present disclosure is directed toward overcoming one or more of the problems discovered by the inventors.